Sedentary Time Volume, Accrual Linked to All-Cause Mortality

TUESDAY, Sept. 12, 2017 (HealthDay News) -- Sedentary time volume and its accrual in prolonged, uninterrupted bouts are associated with increased risk of all-cause mortality, according to a study published online Sept. 12 in the Annals of Internal Medicine.

Keith M. Diaz, Ph.D., from the Columbia University Medical Center in New York City, and colleagues examined the correlation between objectively measured sedentary behavior and all-cause mortality in a prospective cohort study involving 7,985 black and white adults aged 45 years and older. A hip-mounted accelerometer was used to measure sedentary time, with prolonged, uninterrupted sedentariness expressed as mean sedentary bout length. Hazard ratios were calculated comparing quartiles 2 through 4 with quartile 1 for each exposure in models that included moderate to vigorous physical activity.

The researchers found that 340 participants died over a median follow-up of four years. The risk for all-cause mortality was increased with greater total sedentary time and longer sedentary bout duration. The greatest risk of death was seen for participants classified as high for sedentary time (≥12.5 hours/day) and bout duration (≥10 minutes/bout).

"Both the total volume of sedentary time and its accrual in prolonged, uninterrupted bouts are associated with all-cause mortality, suggestive that physical activity guidelines should target reducing and interrupting sedentary time to reduce risk for death," the authors write.